玄武岩纤维混凝土断裂性能实验研究

Experimental study of fracture properties for basalt-fiber-reinforced concrete

为探讨玄武岩纤维混凝土的断裂性能,对31组相对切口深度为0.4的玄武岩纤维混凝土试件进行了三点弯曲实验,分析了玄武岩纤维混凝土的裂纹扩展过程,从断裂韧度、断裂能和延性指数三个方面对玄武岩纤维混凝土的断裂性能进行评价,探讨了玄武岩纤维对混凝土断裂性能的影响机理。结果表明:掺入适量纤维可以有效提高混凝土的断裂韧度、断裂能和延性指数,但这种提高与纤维特征系数不成线性关系。纤维对混凝土的断裂性能同时存在增强和削弱两种影响。通过引入以纤维特征系数为变量的削弱系数和削弱函数,获得了较高精度的各断裂参数关于纤维长径比和体积率的表达式,提出了玄武岩纤维混凝土的配比优化方案,可为玄武纤维混凝土的断裂性能研究提供参考。

In order to investigate the fracture properties of basalt-fiber-reinforced concrete （ BFRC） , we conducted three-points bending experiments to test 31 groups of BFRC specimens with 40 mm middle gap. The crack propaga-tion process is analyzed with respect to fracture toughness, fracture energy, and the ductility index of BFRC. We al-so examined the influencing mechanism of basalt fiber on concrete fractures. The test results indicate that basalt fi-ber can improve the fracture performance of concrete with respect to fracture toughness, fracture energy, and the ductility index, but the reinforcement is not linear with the basalt fiber characteristic index. Fibers may simultane-ously enhance or weaken the fracture performance of concrete. By introducing a weakening coefficient and a weake-ning function, in which fiber characteristics are taken as a coefficient, we obtained the function expressions of the fracture parameters as a volume percentage and slenderness ratio. At last, an optimal scheme for BFRC proportio-ning is also proposed, and our research can provide a theoretical basis for the design and application of BFRC frac-ture properties.